26 C.F.R. § 1.162-14

A corporation which has, for the purpose of computing its excess profits tax credit under Subchapter E, Chapter 2, or Subchapter D, Chapter 1 of the Internal Revenue Code of 1939, elected under section 733 or section 451 (applicable to the excess profits tax imposed by Subchapter E of Chapter 2, and Subchapter D of Chapter 1, respectively) to charge to capital account for taxable years in its base period expenditures for advertising or the promotion of good will which may be regarded as capital investments, may not deduct similar expenditures for the taxable year. See section 263(b). Such a taxpayer has the burden of proving that expenditures for advertising or the promotion of good will which it seeks to deduct in the taxable year may not be regarded as capital investments under the provisions of the regulations prescribed under section 733 or section 451 of the Internal Revenue Code of 1939. See 26 CFR, 1938 ed., 35.733-2 (Regulations 112) and 26 CFR (1939) 40.451-2 (Regulations 130). For the disallowance of deductions for the cost of advertising in programs of certain conventions of political parties, or in publications part of the proceeds of which directly or indirectly inures (or is intended to inure) to or for the use of a political party or political candidate, see § 1.276-1.